I think you are right. We don't want to suffer the same fate as betamax because we didn't want to be associated with naughty stuff. But the reality is, it can't be the job of the core developers to create this type of tool.
Personally I think it is simply the job of the core developers to create digital cash. In my eyes, the fact that Bitcoin lacks privacy features is a defect, not one that I expected Satoshi to solve from day one, but something any cryptocurrency must have. Fungibility makes up part of the value of any currency, loss of privacy causes loss of fungibility, and therefore loss of privacy causes loss of value.
I don't see that because a currency has more privacy features than another, that this quality in way implies that the developers should spend time on services that rely on higher privacy. Rather, services that require privacy should use whatever currency suits their needs, and if it turns out that privacy features are highly valued, the developers can choose to spend their time on that. To do it in reverse puts the capitalist cart before the consumer horse: "because we have made this, we must also make this", rather than "people liked what we made, so we will make more of it".
I'm against a Dash-only fork of OB for two reasons:
First, forks are expensive to maintain. Literally every single change implemented in OB-Bitcoin would have to be merged and tested in OB-Dash. OB-Dash would not find it practical to add Dash-specific features, because if they were not merged into OB-Bitcoin, they would compound the cost of maintaining the fork, as it diverged further and further away. I've seen all this happen in a commercial setting – the company in question was only saved from this eternal nightmare of maintaining an almost (but not quite) equivalent fork when the client of the fork went bankrupt.
Second, it fragments the network. Instead of having people shopping using Bitcoin, and then seeing the occasional listing accepting Dash, and being able to transition incrementally to Dash by making first the odd purchase, then increasingly more over time, they would see nothing of Dash until something compelled them to switch to the alternative network. Instead of having a system where your tape recorder plays both VHS and Betamax, and you choose which tape you want each time, it would create the same constraint as physical hardware, where you have to switch player each time you switch tape format. Software can do much better than this, we don't need to impose the constraints of the past.
